org.grouplens.lenskit.data.dao

Class PrefetchingItemDAO

java.lang.Object

org.grouplens.lenskit.data.dao.PrefetchingItemDAO

All Implemented Interfaces:

ItemDAO, Describable

public final class PrefetchingItemDAO
extends Object
implements ItemDAO, Describable

Item DAO that streams the events to get item information. The item set is fetched and memorized once for each instance of this class.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
PrefetchingItemDAO(EventDAO events)

Method Summary

Modifier and Type	Method and Description
void	describeTo(DescriptionWriter writer) Write this class's description to a sink.
LongSet	getItemIds() Get all known item IDs.
static Function<EventDAO,ItemDAO>	wrapper() A function that wraps an event DAO in a prefetching item DAO.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PrefetchingItemDAO

@Inject
public PrefetchingItemDAO(EventDAO events)

Method Detail

wrapper

public static Function<EventDAO,ItemDAO> wrapper()

A function that wraps an event DAO in a prefetching item DAO. If the DAO already implements ItemDAO, it is returned unwrapped.

Returns:

A wrapper function to make item DAOs from event DAOs.

getItemIds

public LongSet getItemIds()

Description copied from interface: ItemDAO

Get all known item IDs.

Specified by:

getItemIds in interface ItemDAO

Returns:

The set of known item IDs.

describeTo

public void describeTo(DescriptionWriter writer)

Description copied from interface: Describable

Write this class's description to a sink. Anything relevant to this object's identity should be digested; the idea is that, barring hash collisions, two objects with the same digest are equivalent. Used for things like deterministically generating cache file names.

Specified by:

describeTo in interface Describable

Parameters:

writer - The description writer to use.